22 Chapter 2 A rapid overview5.9 The concept of prototype
The brief survey we've just given shows something important. Cate
gories like noun, verb and adjective have not just one property distinguishing them
from each other and from other categories: they have a cluster of distinctive proper
ties. But while there are lots of words that have the full set of properties associated
with their category, there are others which do not. Take equipment, for example. It's
undoubtedly a noun, but it doesn't have a plural form the way nouns generally do.
We use the term prototypical for the central or core members of a category that
do have the full set of distinctive properties.
Cat and dog are examples of prototypical nouns, but equipment is a non
prototypical noun.
Go, know, and tell (and thousands of others) are prototypical verbs, but must is
non-prototypical, because (for example) it has no preterite form (1 musted work
late yesterday is ungrammatical), and it can't occur after to (compare 1 don 't
want to gQ with 1 don 't want to must work late).
Big, old, and happy are prototypical adjectives, while asleep is non-prototypical
because it can't be used attributively (*an asleep child).
We introduce the concept of prototype here because the parts of speech provide
such clear examples of it, but it applies throughout the grammar. It applies to sub
jects, for instance. The NP his guilt, as in the clause His guilt was obvious, is a pro
totypical subject, whereas in That he was guilty was obvious the subordinate clause
that he was guilty is a non-prototypical subject. It differs from his guilt in that it
can't invert with an auxiliary verb to form an interrogative (that is, we don't find
*Was that he was guilty obvious ?).
6 The structure of phrases
A phrase normally consists of a head, alone or accompanied by one or
more dependents. The category of the phrase depends on that of the head: a phrase
with a noun as head is a noun phrase, and so on.
We distinguish several different kinds of dependent, the most important of which
are introduced in the following subsections.6.1 Complement and modifier
The most general distinction is between complements and modifiers,
as illustrated for VPs and NPs in [18], where complements are marked by double
underlining, modifiers by single underlining:[18] I VP
ii NPHe [kept her letters fo r years].
She regularly gives us [very useful advice on financial matters],